1. Field of the Invention
The present invention pertains to a microsurgical instrument having a pair of operative surgical surfaces that are moved relative to each other in shearing or grasping procedures performed by the instrument, where the surgical instrument has an actuator handle with actuators that are radially compressed by the fingers of an operator's hand in controlling the movement of the operative surgical surfaces.
2. Description of the Related Art
Microsurgical instruments are those types of surgical instruments employed in performing surgical operations on extremely small and extremely delicate parts of the human anatomy, for example the tissues inside the human eye. There are many different types of microsurgical instruments. The more complex in construction are microsurgical instruments that have at least one pair of operative surgical surfaces that move relative to each other when using the instrument. By operative surgical surfaces what is meant is, for example, the opposed shearing surfaces of a scissors that have shearing edges that move across each other in a shearing operation performed by the instrument, or the opposed grasping surfaces of a forceps that move toward and away from each other in a grasping operation performed by the instrument. In microsurgical instruments of this type, the scale of the instrument must be as small as possible so that the introduction of the instrument to the surgical site is minimally invasive.
A typical microsurgical instrument is comprised of a manual handle that is similar in size and shape to a pen or pencil. This enables the instrument to be easily manipulated by the fingers on one hand of a surgeon. An example of this type of instrument is disclosed in U.S. Pat. No. 5,370,658, assigned to the assignee of the present invention and incorporated herein by reference.
Microsurgical instrument tips of the type disclosed in the above-referenced patent often comprise a hollow, narrow tube projecting from the instrument handle. A narrow fiber or shaft is received in the tube and the shaft and tube are caused to reciprocate relative to each other in response to manual manipulation of some type of actuator on the instrument handle. The relative movement between the shaft and tube operates the surgical instrument formed at the distal ends of the shaft and tube. Where the surgical instrument is a forceps, the opposed jaws of the forceps are formed at the shaft distal end and moving the tube over the shaft or retracting the shaft into the tube causes the forceps jaws to move toward each other. The reverse movements of the tube and shaft cause the jaws to separate from each other. Where the surgical instrument is a scissors, one of the shear surfaces is formed at the distal end of the shaft and the other shear surface is formed at the distal end of the tube. Moving the tube distal end toward the shaft distal end causes the shear surfaces and their shearing edges to move toward and across each other.
As stated earlier, for microsurgical applications, the surgical instruments discussed above must be manufactured in an extremely small scale. The small scale of the microsurgical instrument results in the operative microsurgical surfaces of the instrument moving relative to each other in response to the slightest movement of the instrument actuator by the fingers of the surgeon's hand.